Self-supporting foldable structures and blanks therefor

ABSTRACT

Self-supporting foldable structures made from preformed blanks of sheet materials are provided which are useful for portable barbeque grills and portable seating.

United States Patent Terrand Bernard Grail Sheboygan, Wis. 875,323

Nov. 10, 1969 Dec. 7, 1971 Design Dynamics, Inc. Northfield, lll.

Inventor App]. No. Filed Patented Assignee SELF-SUPPORTING FOLDABLE STRUCTURES AND BLANKS THEREFOR 15 Claims, 16 Drawing Figs.

11.8. CI 126/9 A, 108/115, 229/41 B Int. Cl A47b 3/00, 865d 5/36, F24c 1/16 Field of Search 126/9,'9 A;

References Cited UNITED STATES PATENTS 2/1956 Paige 229/41 B X 7/1958 Hinderer 126/9 A UX 5/1960 Woelky 229/41 B X 10/1962 Laerum 126/9 X 7/1968 Robinson 126/9 A UX Primary Examiner-Charles .1. Myhre Att0rneyJ0hnston, Root, O'Keeffe, Keil, Thompson &

Shurtleff ABSTRACT: Self-supporting foldable structures made from preformed blanks of sheet materials are provided which are useful for portable barbeque grills and portable seating.

PATENTEDDEB mm 3.625195 SHEET 1 [IF 2 INVIiN'IHR.

ATT'YS TERRAND B. GRALL PATENTEDUEE H9?! 3.625.195

SHEET 2 or 2 ilillii! ATT'YS TERRAND B. GRALL SELF-SUPPORTING FOLDABLE STRUCTURES AND BLANKS THEREFOR BACKGROUND OF THE INVENTION The invention is concerned with the manufacture of selfsupporting foldable structures made from preformed blanks of sheet materials, which structures are useful for portable barbeque grills and portable seating. There is a need for a portable barbeque grill which can be folded into a compact flat package, which is also light in weight, is made from inexpensive materials, can be used for a single cookout, and is disposable. There is also a need for a self-supporting foldable seating structure which can be carried as a flat unit ans set up to form a portable seat at golf tournaments and other sporting events where conventional seating is not available.

OBJECTS OF THE INVENTION One of the objects of the present invention is to provide new and improved self-supporting foldable structures made from preformed sheets of blank materials which are capable of being carried as a flat unit and set up to form a portable barbeque grill.

Another object of the invention is to provide a portable barbeque grill of the type described which is made from corrugated paperboard laminated to a heat-resistant metal foil, the surface of which is in contact with live coals when the barbeque grill is in use.

Still a further object of the invention is to provide a barbeque grill of the type described in the form of a two-component package, one component being the self-supporting foldable structure, and the other being a grill adapted to fit transversely in said structure-after it has been opened and set up.

A further object of the invention is to provide a barbeque grill of the type described with modifications adapted to improve the heat resistance of the structure.

An additional object of the invention is to provide a selfsupporting foldable structure which when folded is normally flat and which can be unfolded and set up to form a seating structure.

Another object of the invention is to provide a seating structure of the type described which is light in weight, is made from readily available inexpensive sheet materials and is fully portable. Other objects will appear hereinafter.

THE DESCRIPTION OF THE INVENTION The invention requires the use of a blank of sheet material which is provided with fold lines and has its edges fastened together in such a way as to form a flat folded unit which can be opened to produce a self-supporting structure. The blank can be made of any suitable sheet material which is sufficiently rigid so that the structure as a whole will be self-supporting. In general, it is preferable to use corrugated paperboard or laminated metal foil and corrugated paperboard but the invention does not preclude the use of other types of sheet materials having the necessary rigidity including plastic sheet materials, metal sheet materials, laminated and stiffened cloths, or combinations of sheet materials. The type of sheet material employed will depend to a considerable extent upon the end use of the resultant structure.

For the purpose of the invention the blank of sheet material from which the self-supporting foldable structure is formed should comprise two outer and at least one intermediate equal area rectangular panels having sides of x and y dimensions, the 1: dimensions not exceeding the y dimensions, said panels having outside fold lines at their adjacent edges, a single inside fold line running diagonally from corner to corner of each panel, said diagonal inside fold lines in said panels being parallel to one another, and a single inside fold line in said intermediate panel bisecting the x dimensions of said intermediate panel and parallel to the y dimensions of said intermediate panel. There are preferably only three rectangular panels and these are preferably square.

In order to form a self-supporting structure from the previously described blank, the opposite sides of said blank are secured together, the outermost panels are folded opposite one another and the immediate panel is folded inwardly between said outermost panels along said bisecting fold line, whereby when the upper edges of said folded structure are pulled apart laterally a'self-supporting structure is formed having opposing pyramids, one inverted with respect to the other and with common apices. When the blank contains only three rectangular panels, the pyramids are three sided.

In making such a structure for use as a barbeque grill, the sheet material should be fire resistant, at least in the areas forming the inside surfaces of the inverted pyramid. This is preferably accomplished by laminating to such surface a fire resistant metal foil, as, for example, a foil of aluminum or copper. According to a modification of the invention, the sheet material which normally forms a backing for such foil is cut away in the areas forming the sides of said inverted pyramid where live coals would normally be in contact with the metal foil when the barbeque grill is being used. According to another modification of the invention, the inside surface of the inverted pyramid is formed from corrugated fire-resistant metal foil with the tips of the corrugations facing inwardly so that live coals will be in contact with the tips of the corrugations, leaving air spaces between the coals and the sides of the inverted pyramid. This corrugated fire-resistant metal foil can also be a separate member or members adapted to be inserted against the sides of the inverted pyramid.

According to another modification of the invention, a fireresistant metal foil can be laminated to the sheet material which fonns the main supporting structure so that both of the opposing pyramids are lined with a fire-resistant metal foil. In this way, after the portable barbeque unit has been used once, the grill can be removed and the unit turned upside down after which the grill is inserted in the pyramid which then occupies the upper position.

In another embodiment of the invention the self-supporting structure is used to provide a seating. This can be accomplished by inserting a seating unit in the inverted pyramid or by adding an additional panel to one side of the blank which is a side of the base of the inverted pyramid. This panel has dimensions corresponding to the dimensions of the base of the inverted pyramid and can be folded to form a flat package when the supporting structure is collapsed.

THE DRAWINGS In the drawings,

FIG. 1 is a perspective view of one embodiment of the invention illustrating a barbeque grill provided in accordance with the invention.

FIG. 2 is an exploded perspective view showing the manner in which the grill is inserted into the main body of the supporting structure;

FIG. 3 is a plan view of a blank of sheet material used in constructing the barbeque unit shown in FIGS. I and 2;

FIG. 4 is a perspective view illustrating the first step in folding the blank of FIG. 3;

FIG. 5 is a perspective view illustrating the second step in which the outer ends of the outer panels of the blank of FIG. 3 are secured together; I

FIG. 6 is a cross sectional view taken along the lines 6-6 of FIG. 1 and showing the upper part of FIG. 1 in phantom;

FIG. 7 is a collapsed plan view of the flat folded blank of FIG. 5 after the outer ends have been secured together;

FIG. 8 is a plan view of a modified form of blank which is similar to the blank of FIG. 3 except that portions of the sheet material which form a backing for the metal foil are cut away in the areas which would normally be exposed to high temperatures when the structure is in use as a barbeque unit;

FIG. 9 illustrates a modification of the invention in which a corrugated metal foil is disposed on the inside surfaces of the inverted pyramid of the barbeque unit with the tips of the corrugations facing inwardly;

FIG. is a perspective view of another embodiment of the invention wherein the structure is used as portable seating;

FIG. 11 is a perspective exploded view showing the manner in which an additional supporting element can be inserted in the inverted pyramid structure to strengthen the resultant structural unit when used as a seating structure;

FIG. 12 is a plan view of a blank used to form the seating structure shown in FIG. 10;

FIG. 13 is a perspective view showing the first step of folding the blank of FIG. 12,

FIG. 14 is a perspective view showing the manner in which the outer ends of the blank of FIG. 12 are secured together;

FIG. is a cross-sectional view taken along the line 1515 of FIG. 10 with the upper part of the structure shown in phantom; and

FIG. 16 is a collapsed plan view of the structural unit shown in FIG. 14.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION Referring to FIG. 3 the blank of corrugated sheet material having aluminum foil laminated on one side thereof, or other suitable sheet material, is generally shown at l and comprises rectangular panels A, B and C. These panels have x and y dimensions, the x dimensions not exceeding the y dimensions. In the particular blank shown in FIG. 3, the x and y dimensions are the same and hence the panels A, B and C are square. The size of these panels can be varied but suitable dimensions for the purpose of the invention are inches on each side, i.e., x=20 inches and y=20 inches. A suitable sheet material for forming the blank I is a double faced corrugated paperboard approximately one-eighth-inch thick laminated on one side with aluminum foil. The aluminum foil should be of sufficient thickness to withstand temperature conditions normally encountered when hot coals are brought into contact therewith.

In the blank shown in FIG. 3 the solid vertical lines are outside fold lines and the dotted lines are inside fold lines.

Each of the panels A, B and C has a single inside fold line running diagonally from corner to comer as shown at 2, 3 and 4. These diagonal inside fold lines are parallel to one another. The panel B has a single inside fold line 5 bisecting the sides 6 and 7 and parallel to the sides 8 and 9.

The panel A has an outer side [0 and two opposing sides 11 and 12. The panel C has an outer side 13 and two opposing sides 14 and 15.

In assembling the structure, the first step shown in FIG. 4 involves bending the blank 1 along fold lines 8 and 9 and then forming an inner fold along line 5. The edges 10 and 13 are then secured together by means of a binding strip 16 which can be in the form of adhesive tape or an adhesively coated paper strip. This is secured over the ends 10 and 13 so as to bind them together. The resultant structural unit in its folded state is substantially flat as shown in FIG. 7.

When the upper edges 11 and 14 are grasped and pulled apart laterally, a self-supporting structure is fonned having opposing pyramids, one inverted with respect to the other and with common apices. The inverted pyramid 17 in FIG. 2 has at least the lower part of its inner surface lined with aluminum foil or other suitable heat-resistant metal foil. When the unit is used as a barbeque unit, charcoal briquettes are placed in the bottom of the inverted pyramid I7 and are in contact with the metal foil lining. It is not absolutely necessary that the metal foil lining cover the upper parts of the inner surface of the pyramidal unit 17 so long as these parts are not brought into contact with live coals.

A grill 18 which can also be made of corrugated paperboard covered with aluminum foil or other heat-resistant metal foil has dimensions such that it will fit transversely inside inverted pyramid 17 adjacent the open end thereof.

According to a modification as shown in FIG. 8, portions of the blank on the outside of the metal foil are cut away from the panels A, B and C. These cut away portions generally shown at I9, 20 and 21 in FIG. 8 are triangular and slightly offset with respect to the fold lines 2, 3 and 4, respectively. The offset portion when the structure is erected constitutes an area in the supporting surface closest to the bed of coals in the inverted pyramidal space 17. Thus, the removal of this area assists in protecting the supporting portions of the structure against high temperatures.

In the modification shown in FIG. 9 the inner surface of the inverted pyramid 17 is constructed with the metal foil of aluminum or other suitable material 22 corrugated with the tips of the corrugations 23 extending inwardly and adapted to support charcoal briquettes 24 or similar types of fuel. The outwardly extending tips of the corrugations of the metal foil 22 are laminated to corrugated paperboard 25 of the blank 1.

In the embodiment of the invention illustrated in FIGS. 10 to 16, which is a seating structure, the blank 26, which is made of doublefaced corrugated paperboard or other suitable selfsupporting sheet material, is generally similar to the blank shown in FIG. 3 except that it has an additional panel D. The panels A, B and C correspond to panels A, B and C in FIG. 3, and the fold lines 2, 3, 4',5, 8 and 9 correspond to the fold lines 2, 3, 4, 5, 8 and 9 in FIG. 3. The upper and lower edges 6' and 7 of the intermediate panel B correspond to edges 6 and 7 ofpanel B in FIG. 3. The edges I0, 11 and 12' of panel A correspond to edges 10, 11 and 12 of panel A of FIG. 3. The edges 13, 14' and 15 of panel C correspond to edges I3, 14 and 15 of panel C of FIG. 3. Panel D has edges 27 and 28.

The manner in which the blank of FIG. 12 is folded is illustrated by FIG. 13 wherein the first step involves bringing the edges 10 and 13' toward one another and folding the fold line 5 inwardly. In the second step shown in FIG. 14 an adhesive tap 16 which corresponds to the tap 16 in FIG. 5, is used to fasten together the edges 10' and 13. The resultant structure in its collapsed condition has the panel D in contact with panel A and the panel B folded inwardly along fold line 5' between panel A and panel C as shown in FIG. 16.

When edges 11 and 14' are grasped and pulled laterally, the structure will open along the diagonal fold lines 2', 3' and 4, thereby causing the fold line 5 to move outwardly at the top of the structure and producing two pyramids, the upper pyramid being inverted with respect to the lower pyramid and the apices of said pyramids being at substantially the same point. The inverted pyramid 17 provides a space which is adapted to receive a reenforcing element 29 as shown in FIG. 11. This element can be made of any self-supporting sheet material, such as corrugated paperboard, plastic sheet materials, fabric sheet materials or combinations of these. It comprises a triangular panel 30, a second triangular panel 31 and a double panel 32 adapted to fit within the inverted pyramid I7 and serve as a reenforcement. These panels are disposed at angles of approximately with respect to one another and the dimensions of their outer edges are preferably such that they will coincide with the inner edges of the inverted pyramid 17'. Also, the top surface of the element 29 should be slightly below the level of the panel D. The panel D is then folded downwardly in the direction of the arrow as shown in FIG. 11

to form a seating surface. The resultant seating structure has the general appearance shown in FIG. 10.

As shown in FIG. 15, which is a cross section taken along the line 15,15 of FIG. 10, an unusually strong suppon is provided due to the fact that panels A, B and C buttress one another along a transverse plane taken through the central part of the structure. This provides a double fold of sheet material in a horizontal plane through the approximate point of intersection of the apex of the lower pyramid and the apex of the inverted pyramid. The double folds of the panels A, B and C meet at angles of 120. The sides of the bases of the two pyramids are also at an angle of 120 with respect to one another. Thus, the side 11' is at an angle of 120 with respect to the side 12. The side 6' is at an angle of 120 with respect to the side 7 and the side 14 is at an angle of 120 with respect to the side 15.

The invention provides unique and useful portable structures for barbeque units and seating units. These structures are made from readily available sheet materials and are relatively simple to manufacture and assemble. In the folded or collapsed form these structures make a convenient package. In the barbeque unit the grill 18 can be carried within the folded unit. Likewise in the portable seating structure the reenforcing unit 29 can be folded and carried within the collapsed unit. In either case, these units are relatively light in weight and fully portable.

It will be recognized that the invention is susceptible to some variation and modification, particularly in the choice of materials used in the construction and that some alterations can be made without departing from the scope of the invention.

The invention is hereby claimed as follows:

1. A blank of sheet material for forming a self-supporting foldable structure comprising two outer and at least one intermediate equal area rectangular panels having sides of x and y dimensions, the x dimensions not exceeding the y dimensions, said panels having outside fold lines at their adjacent edges, a single inside fold line running diagonally from corner to comer of each panel, said diagonal inside fold lines in said panels being parallel to one another, and a single inside fold line in said intermediate panel bisecting the x dimensions of said intermediate panel and parallel to the y dimensions of said intermediate panel.

2. A blank as claimed in claim 1 having only three rectangular panels.

3. A blank as claimed in claim 1 in which said rectangular panels are square.

4. A blank as claimed in claim 2 in which said rectangular panels are square.

5. A self-supporting foldable structure comprising a blank as claimed in claim 1 in which the opposite sides of said blank are secured together, the outermost panels are folded opposite one another and the intermediate panel is folded inwardly between said outermost panels along said bisecting fold line, whereby when the upper edges of said folded structure are pulled apart laterally a self-supporting structure is formed having opposing pyramids one inverted with respect to the other and with common apices.

6. A structure as claimed in claim 5 in which said pyramids are three sided.

7. A structure as claimed in claim 5 in which said sheet material is fire resistant at least in areas forming the inside surfaces of said inverted pyramid.

8. A structure as claimed in claim 7 in which said sheet material comprises a fire-resistant metal foil.

9. A structure as claimed in claim 5 in which said sheet material comprises a fire-resistant metal foil laminated to a stiff corrugated paperboard.

10. A portable barbeque grill comprising a structure as claimed in claim 7 having a grill disposed transversely adjacent the base of said inverted pyramid.

11. A portable barbeque grill comprising a structure as claimed in claim 7 in which said sheet material comprises a fire-resistant metal foil laminated to a stiff corrugated paperboard, said paperboard being cut away at least in part of the areas forming the sides of said inverted pyramid.

12. A portable barbeque grill comprising a structure as claimed in claim 7 wherein areas on the inside surfaces of said inverted pyramid are formed from corrugated fire-resistant metal foil with the tips of the corrugations facing inwardly.

13. A two-component package portable barbeque grill adapted to be carried in flat folded condition and to be unfolded to a self-sustaining structure, one of said components being a structure as claimed in claim 7 and the other being a grill adapted to fit transversely in said inverted pyramid adjacent the open end thereof.

14. A portable seating structure comprising a structure as claimed in claim 5 having a seating surface adjacent the base of said inverted yramid.

15. A portab e seating structure as claimed in claim 14 in which the seating surface is secured to one side of the base of the inverted pyramid, has dimensions corresponding to the dimensions of said base, and can be folded to form a flat package when the supporting structure is collapsed.

IF i I I l 

1. A blank of sheet material for forming a self-supporting foldable structure comprising two outer and at least one intermediate equal area rectangular panels having sides of x and y dimensions, the x dimensions not exceeding the y dimensions, said panels having outside fold lines at their adjacent edges, a single inside fold line running diagonally from corner to corner of each panel, said diagonal inside fold lines in said panels being parallel to one another, and a single inside fold line in said intermediate panel bisecting the x dimensions of said intermediate panel and parallel to the y dimensions of said intermediate panel.
 2. A blank as claimed in claim 1 having only three rectangular panels.
 3. A blank as claimed in claim 1 in which said rectangular panels are square.
 4. A blank as claimed in claim 2 in which said rectangular panels are square.
 5. A self-supporting foldable structure comprising a blank as claimed in claim 1 in which the opposite sides of said blank are secured together, the outermost panels are folded opposite one another and the intermediate panel is folded inwardly between said outermost panels along said bisecting fold line, whereby when the upper edges of said folded structure are pulled apart laterally a self-supporting structure is formed having opposing pyramids one inverted with respect to the other and with common apices.
 6. A structure as claimed in claim 5 in which said pyramids are three sided.
 7. A structure as claimed in claim 5 in which saiD sheet material is fire resistant at least in areas forming the inside surfaces of said inverted pyramid.
 8. A structure as claimed in claim 7 in which said sheet material comprises a fire-resistant metal foil.
 9. A structure as claimed in claim 5 in which said sheet material comprises a fire-resistant metal foil laminated to a stiff corrugated paperboard.
 10. A portable barbeque grill comprising a structure as claimed in claim 7 having a grill disposed transversely adjacent the base of said inverted pyramid.
 11. A portable barbeque grill comprising a structure as claimed in claim 7 in which said sheet material comprises a fire-resistant metal foil laminated to a stiff corrugated paperboard, said paperboard being cut away at least in part of the areas forming the sides of said inverted pyramid.
 12. A portable barbeque grill comprising a structure as claimed in claim 7 wherein areas on the inside surfaces of said inverted pyramid are formed from corrugated fire-resistant metal foil with the tips of the corrugations facing inwardly.
 13. A two-component package portable barbeque grill adapted to be carried in flat folded condition and to be unfolded to a self-sustaining structure, one of said components being a structure as claimed in claim 7 and the other being a grill adapted to fit transversely in said inverted pyramid adjacent the open end thereof.
 14. A portable seating structure comprising a structure as claimed in claim 5 having a seating surface adjacent the base of said inverted pyramid.
 15. A portable seating structure as claimed in claim 14 in which the seating surface is secured to one side of the base of the inverted pyramid, has dimensions corresponding to the dimensions of said base, and can be folded to form a flat package when the supporting structure is collapsed. 